A Diachronic Study of Initial Stress and other Prosodic Features in the French News Announcer Style: Corpus-based Measurements and Perceptual Experiments

Abstract

This study focuses on prosodic evolution in the French news announcer style, based on acoustic and perceptual analysis of French audiovisual archives. A 10-hour corpus covering six decades of broadcast news is investigated automatically. Two prosodic features, which may give an impression of emphatic style, are explored: word-initial stress and penultimate vowel lengthening, especially before a pause. Objective measurements suggest that the following features have decreased since the 40s: mean pitch, pitch rise associated with initial stress, vowel duration characterizing an emphatic initial stress, and prepausal penultimate lengthening. The onsets of stressed initial syllables have become longer while speech rate (measured at the phonemic level) has not changed. This puzzling outcome raises interesting questions for research on French prosody, suggesting that the durational correlates of word-initial stress have changed over time, in the French news announcer style. Three perceptual experiments were conducted using prosody transplantation (copy of fundamental frequency and duration parameters on a synthetic voice), delexicalization and imitation. Rather than manipulating the parameters of,say, word-initial stress, we selected a subset of the corpus to represent the different decades under investigation. Results show that, among other factors, fundamental frequency and duration correlates of prosody contribute to distinguishing early recordings from more recent ones.The higher the pitch and the greater the pitch movements associated with word-initial stress, the more the speech samples are perceived as dating back to the 40s or 50s.